Green Tea and Catechins

J Cell Biochem. 2010 May 15;110(2):333-42. doi: 10.1002/jcb.22541.

Effects of catechin, epicatechin and epigallocatechin gallate on testosterone production in rat leydig cells. 

Catechins are a type of antioxidant found in the greatest abundance in the leaves of the tea plant Camellia sinensis. Thirty-six percent of green tea is composed by tea polyphenols, in which 80% is composed by flavonoids [Chung and Landau, 2000]. The major contents of flavonoids are catechins, for example, CCN, EC, epicatechin gallate (ECG), epigallocatechin (EGC), and EGCG In the study, the effects of catechins on testosterone secretion in rat testicular Leydig cells (LCs) were explored. Both in vivo and in vitro investigations were performed. These results suggested that catechins stimulated testosterone production by acting on rat LC. 

In the in vivo study, 8 groups of 6-7 mice were  were injected with saline (1 ml/kg) as vehicle, CCN (1 µg/ml/kg), EC (1 µg/ml/kg), EGCG (1 µg/ml/kg), human chorionic gonadotropin (hCG, 5 IU/ml/kg), hCG + CCN, hCG + EC, and hCG + EGCG via the jugular catheter.Basically they fed the mice either 1 microgram EGCG, catechin, epicatechin or some combination per kg bodyweight of the mice.

Results of in vivo study showed that the concentration of plasma testosterone increased significantly 8 h later after treated with CCN. The same reaction was also noted when treated with EC and EGCG, respectively (Fig. a). The concentration of plasma testosterone increased significantly when male rats treated with hCG and this phenomenon sustained for 8 h (P < 0.01, Fig. b). The same reaction was also noted when treated with hCG + CCN or hCG + EC. However, the concentration of plasma testosterone increased significantly when treated with hCG + EC compared to the hCG alone (P < 0.05, Fig. b) at 2 and 8 h.

Conclusion: Catechins increased plasma testosterone in vivo in male rats